Vibrator manufacturing method

ABSTRACT

A method of manufacturing a vibration type actuator providing a satisfactory actuator performance even when an increase in speed is achieved and having a contact spring. The actuator includes an elastic member and a hollow protrusion having a side wall portion protruding with respect to a surface of the elastic member, a contact portion configured to come into contact with a body, and a first connection portion connecting the side wall portion and the contact portion, the method includes, forming the hollow protrusion including the side wall portion and a distal end portion by performing drawing on an elastic plate and forming the contact portion and the first connection portion by performing drawing or squeezing on the distal end portion, wherein the contact portion is surrounded by the first connection portion.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.14/612,151, filed Feb. 2, 2015, which claims priority to U.S. Pat. No.8,981,619, issued Mar. 17, 2015, which claims priority from JapanesePatent Application No. 2010-087891 filed Apr. 6, 2010, all of which arehereby incorporated by reference herein in their entirety.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to a vibration type actuator generatingvibration in a vibrator to cause a driven body to make a relativemovement, a vibrator of a vibration type actuator, and a vibratormanufacturing method.

Description of the Related Art

In a vibration type actuator, a contact portion to be brought into presscontact is endowed with resiliency, whereby a smooth contact can berealized, and a satisfactory performance can be obtained. As illustratedin FIG. 11, in a linear vibration type actuator discussed in JapanesePatent Application Laid-Open No. 2008-125147, a vibrator 110 is providedwith protrusions 119 each equipped with a contact portion 113 exhibitingresiliency.

The protrusion 119 is composed of the contact portion 113 having acontact surface 114 to be brought into contact with a driven body (notillustrated), a fixation portion 117, and a connection portion 116connecting the contact portion 113 and the fixation portion 117, and thefixation portion 117 is fixed to an elastic member 112 by laser weldingor the like. In order that the contact portion 113 may exhibitresiliency, the elastic member 112 is provided with a groove portion 118of a sufficient depth. The elastic member 112 is provided on apiezoelectric member 115.

The provision of a vibrator with a contact portion with resiliency isnot limited to a linear vibration type actuator. As discussed inJapanese Patent Application Laid-Open No. 2006-311790, there exists arotary vibration type actuator for generating a progressive wave in anelastic member whose vibrator has at the distal end of a protrusionthereof a resilient contact portion joined thereto.

However, the conventional constructions described above have thefollowing problems. In the linear vibration type actuator discussed inJapanese Patent Application Laid-Open No. 2008-125147, to increase themoving speed of the driven body, it is necessary to heighten the contactsurfaces 114 of the vibrator 110, which are brought into contact withthe driven body, to thereby enlarge the vibration amplitude in thefeeding direction (the X-direction).

However, heightening the contact surface 114 results in a reduction inthe rigidity in the X-direction of the connection portions 116, so that,although high vibration speed can be attained, it is difficult totransmit drive force efficiently to the driven body. Further, since theresonance frequency of the vibration mode in which the protrusions 119vibrate is reduced, unnecessary vibration is likely to be generated, sothat, in some cases, it is difficult to obtain a satisfactory actuatorperformance.

Also regarding the rotary vibration type actuator as discussed inJapanese Patent Application Laid-Open No. 2006-311790, heightening thecontact surfaces results in a reduction of the rigidity in theperipheral and radial directions, and unnecessary vibration may easilyoccur.

SUMMARY OF THE INVENTION

According to an aspect of the present invention, a vibration typeactuator includes a vibrator equipped with an electrical-mechanicalenergy conversion element, an elastic member to which theelectrical-mechanical energy conversion element is fixed, and aprotrusion provided on the elastic member, and the vibrator beingconfigured to generate an elliptic movement in the protrusion, and adriven body configured to contact with the protrusion and to moverelatively to the vibrator, wherein the protrusion includes a contactportion having a contact surface contacting the driven body, acontinuous side wall portion protruding with respect to one end surfaceof the elastic member and forming a hollow structure, and a connectionportion connecting the contact portion and the side wall portion andexhibiting flexibility in a direction normal to the contact surface.

According to another aspect of the present invention, a vibratorincludes an electrical-mechanical energy conversion element, an elasticmember to which the electrical-mechanical energy conversion element isfixed, and a protrusion provided on the elastic member, is the vibratorbeing configured to generate an elliptic movement in the protrusion tothereby cause a driven body to make a relative movement, wherein theprotrusion includes a contact portion having a contact surfacecontacting the driven body, a continuous side wall portion protrudingwith respect to one end surface of the elastic member and forming ahollow structure, and a connection portion connecting the contactportion and the side wall portion and exhibiting flexibility in adirection normal to the contact surface.

According to yet another aspect of the present invention, a method ofmanufacturing a vibrator equipped with an electrical-mechanical energyconversion element, an elastic member to which the electrical-mechanicalenergy conversion element is fixed, and a protrusion provided on theelastic member, and the vibrator being configured to cause a driven bodycontacting the protrusion to make a relative movement, includesperforming press molding on the elastic member to thereby form acontinuous side wall portion protruding from the elastic member andforming a hollow structure, a contact portion having a contact surfaceconfigured to contact the driven body, and a connection portionconfigured to connect the side wall portion and the contact portion andhave flexibility in a direction normal to the contact surface, andpunching the elastic member to shape the vibrator.

According to the present invention, the side surface of the protrusionis continuously connected with the contact surface of the protrusion ofthe vibration type actuator while exhibiting resiliency in theZ-direction, so that it is possible to ensure rigidity in the X- andY-directions, thereby making it possible to obtain a satisfactoryactuator performance.

Further features and aspects of the present invention will becomeapparent from the following detailed description of exemplaryembodiments with reference to the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of the specification, illustrate exemplary embodiments, features,and aspects of the invention and, together with the description, serveto explain the principles of the invention.

FIG. 1A is a perspective view of a vibrator according to a firstexemplary embodiment of the present invention, and

FIG. 1B is a perspective view, partly in section, of a protrusionthereof.

FIG. 2A is a perspective view of a vibrator according to a secondexemplary embodiment of the present invention, and

FIG. 2B is a perspective view, partly in section, of a protrusionthereof.

FIG. 3A is a perspective view of a vibrator according to a thirdexemplary embodiment of the present invention, and

FIG. 3B is a perspective view, partly in section, of a protrusionthereof.

FIG. 4 is a perspective view of a ring-shaped vibrator according to afourth exemplary embodiment of the present invention.

FIG. 5A is a perspective view of a vibrator according to a fifthexemplary embodiment of the present invention, and

FIG. 5B is a perspective view, partly in section, of a protrusionthereof.

FIGS. 6A to 6F are diagrams illustrating an integral press moldingprocess performed on an elastic member.

FIG. 7A is a perspective view of a vibrator according to a sixthexemplary embodiment of the present invention, and

FIG. 7B is a perspective view, partly in section, of a protrusionthereof.

FIGS. 8A to 8E are diagrams illustrating an integral press moldingprocess performed on the elastic member of FIGS. 7A and 7B.

FIG. 9 is an external perspective view of a conventional linearvibration type actuator.

FIGS. 10A and 10B are diagrams illustrating two vibration modes in whichexcitation is effected by the vibrator of FIG. 9.

FIG. 11 is a perspective view of a vibrator on which protrusions withresiliency are mounted, and of one of the protrusions.

FIG. 12A is a perspective view of a vibrator according to a modificationexample of the fifth exemplary embodiment of the present invention, andFIG. 12B is a perspective view, partly in section, of a protrusionthereof.

DESCRIPTION OF THE EMBODIMENTS

Various exemplary embodiments, features, and aspects of the inventionwill be described in detail below with reference to the drawings.

In a first exemplary embodiment, a vibrator applicable to a linearvibration type actuator will be described. First, the driving principlethereof will be described with reference to FIGS. 9, 10A, and 10B.

FIG. 9 is a schematic perspective view of a linear vibration typeactuator. In FIG. 9, a linear vibration type actuator 200 is composed ofa vibrator 100 and a slider 106 constituting a driven body. The vibrator100 has a piezoelectric element 105, which is an electrical-mechanicalenergy conversion element formed as a rectangular thin plate, an elasticmember 102 joined to one end surface of the piezoelectric element 105,and two protrusions 103 formed so as to protrude from the elastic member102.

FIGS. 10A and 10B are diagrams illustrating how the vibrator illustratedin FIG. 9 is deformed through excitation in two vibration modes (MODE-Aand MODE-B), respectively. Here, both of the two vibration modes arebending vibration modes in out-of-plane directions with respect to thevibrator 100. The configuration of the vibrator 100 is selected so thatthe resonance frequencies substantially coincide with each other.

The two diagrams located downside in FIG. 10A illustrate the vibrator100 as seen from the Y-direction. As illustrated in the diagram at thebottom of FIG. 10A, the vibration of MODE-A is a vibration of asecondary bending vibration mode in which there appear three nodes (α),which extend in the Y-direction of the vibrator 100.

The protrusions 103 are arranged at positions in the vicinity of thenodes in the vibration of MODE-A, and in the vibration of MODE-A, thereis generated in them a reciprocating movement causing the contactsurfaces to be displaced in the X-direction (a direction which isparallel to the contact surfaces and which constitutes the driven bodyfeeding direction) as indicated by the arrows.

The two diagrams located downside in FIG. 10B illustrate the vibrator100 as seen from the X-direction. As illustrated in the diagram at thebottom of FIG. 10B, the vibration of MODE-B is a vibration of a primarybending vibration mode in which there appear two vibration nodes (β),which extend in the X-direction of the vibrator 100. That is, thevibration nodes of MODE-A and the vibration nodes of MODE-B areorthogonal to each other in an XY-plane.

As illustrated in FIG. 10B, the protrusions 103 are situated in thevicinity of positions constituting the antinodes in the vibration ofMODE-B, and through the vibration of MODE-B, there is generated in theprotrusions 103 a reciprocating movement causing the contact surfaces tobe displaced in the Z-direction (a direction which is perpendicular tothe contact surfaces and which is a push-up direction) as indicated bythe arrow.

When AC signals differing in time phase by approximately π/2 are inputto two electrodes (not illustrated) provided in the piezoelectricelement 105, vibrations of MODE-A and MODE-B described above aregenerated through excitation in the vibrator 100 in such a manner thatthe difference in time phase is approximately ±π/2. The vibrations ofthe two vibration modes are synthesized, whereby an elliptic movement inthe XZ-plane in FIG. 9 is generated in the contact surfaces 104 of theprotrusions 103. Due to this elliptic movement, the slider 106, which isbrought into press contact with the contact surfaces 104, makes arelative movement with respect to the vibrator 100.

It should be noted, however, that, in the linear vibration type actuatorof the present exemplary embodiment, the method of generating anelliptic movement in the contact surfaces is not limited to theabove-described one. For example, it is also possible to combine witheach other vibrations of vibration modes different from theabove-described ones, or to combine with each other a vibration of avertical vibration mode expanding and contracting the elastic member inthe X-direction and a vibration of a bending vibration mode.

In other words, it is possible to adopt any type of drive system so longas it is one generating an elliptic movement in the contact surfacesthrough combination of a vibration substantially of a vibration mode fordisplacing the contact surfaces in the feeding direction and a vibrationin a vibration mode for displacing the contact surfaces in thepushing-up direction.

Next, a specific construction of the vibrator of the first exemplaryembodiment will be described. FIG. 1A is a perspective view of avibrator to which the first exemplary embodiment of the presentinvention is applicable, and FIG. 1B is a perspective view, partly insection, of a protrusion thereof. The actuator of the present exemplaryembodiment is a linear vibration type actuator. As its drivingprinciple, the drive system of the conventional linear vibration typeactuator described above is applicable.

As illustrated in FIG. 1A, a vibrator 10 has a piezoelectric element 15formed as a rectangular thin plate, an elastic member 12 fixed to thepiezoelectric element 15, and two protrusions 19 protruding from one endsurface of the elastic member 12 (e.g., from the surface on the oppositeside of the surface to which the piezoelectric element 15 is bonded). Inthe present exemplary embodiment, it is possible to provide only oneprotrusion or a plurality of protrusions as in the present exemplaryembodiment. Further, the protrusions 19 may be provided on the surfaceon the side to which the piezoelectric element 15 is joined.

As illustrated in FIG. 1B, each protrusion 19 has a rectangular sidewall portion 14 of a hollow structure protruding with respect to theelastic member 12, a contact portion 16 having a contact surface 17 tobe brought into contact with a slider (the driven body) (notillustrated), and a connection portion 11 connecting the side wallportion 14 and the contact portion 16. As in the present exemplaryembodiment, in the case where the protrusions 19 are fixed to theelastic member 12, there is provided a fixation portion 13 joined to theupper surface of the elastic member 12 by laser welding or the like.

The side wall portion 14 is continuous (i.e., continuous in a tubularfashion over the entire periphery of the protrusion 19), so that apredetermined rigidity in the in-XY-plane direction is secured for theprotrusion 19. A step is provided between the connection portion 11 andthe contact portion 16, with the upper surface of the connection portion11 being lower than the contact surface 17 of the contact portion 16.That is, the contact surface 17 protrudes farther toward the driven bodyside (the side opposite to the elastic member side) than the driven bodyside surface (the surface on the side opposite to the elastic memberside) of the connection portion 11.

With this structure, the slider does not come into contact with theconnection portion 11. Further, the connection portion 11 is thinnerthan the contact portion 16, and, in addition, the width of theconnection portion 11 is reduced through division into two by holeportions 18, so that it is reduced in rigidity in the Z-direction and isendowed with resiliency (flexibility). In the case where a predeterminedlevel of resiliency can be obtained solely through a reduction in itsthickness, there is no need to divide the connection portion 11 into aplurality of parts by the hole portions 18.

Due to the above construction, the protrusion 19 has resiliency in theZ-direction (the direction of the normal to the contact surface), sothat it is possible to realize a smooth contact between the vibrator 10and the slider. Further, even if the height of the protrusion 19 isincreased for higher speed, the requisite rigidity is secured for theprotrusion 19 in the X-direction, which is the driving direction of theslider, due to the continuous side wall portion 14 in its periphery, sothat it is possible to transmit the drive force of the vibrator 10efficiently to the slider.

Further, the protrusion 19 has at its distal end a portion havingresiliency, so that the resonance frequency of the vibration modethereof is sufficiently higher than the drive frequency of the vibrator10, making it possible to obtain a satisfactory actuator performance.

A vibrator according to a second exemplary embodiment differs from thatof the first exemplary embodiment in that the protrusions are of acylindrical configuration. FIG. 2A is a perspective view of a vibratorto which the second exemplary embodiment of the present invention isapplicable, and FIG. 2B is a perspective view, partly in section, of aprotrusion of the vibrator. The present exemplary embodiment is alsoapplied to a linear vibration type actuator, and its driving principleis the same as that of the conventional linear vibration type actuator,so that the description thereof will be omitted.

As illustrated in FIG. 2A, a vibrator 20 has a piezoelectric element 25,an elastic member 22 fixed to the piezoelectric element 25, and twoprotrusions 29 protruding from one end surface of the elastic member 22.As illustrated in FIG. 2B, each protrusion 29 has a cylindrical sidewall portion 24 provided so as to protrude from the elastic member 22, acontact portion 26 having a contact surface 27 to be brought intocontact with a slider (not illustrated), and connection portions 21connecting the side wall portion 24 and the contact portion 26.

The side wall portion 24 is fixed to the elastic member 22 by laserwelding or the like through the intermediation of a fixation portion 23.Since the side wall portion 24 is continuous over the entire peripheryof the protrusion 29, a predetermined level of rigidity is secured forthe protrusion 29 with respect to the in-XY-plane direction. A step isprovided between the connection portion 21 and the contact portion 26,and the upper surface of the connection portion 26 is lower than thecontact surface 27, so that the slider does not come into contact withthe connection portion 21.

The connection portion 21 is thinner than the contact portion 26, andfurther, the connection portion 21 is divided into four by hole portions28 to be reduced in width, so that it is reduced in rigidity in theZ-direction to be endowed with a predetermined level of resiliency. Inthe case where the predetermined level of resiliency can be obtainedsolely through a reduction in thickness, there is no need for theconnection portion 21 to be divided by the hole portions 28.

With this construction, the protrusion 29 exhibits resiliency in theZ-direction, so that it is possible to realize a smooth contact betweenthe vibrator 20 and the slider. Further, if the height of the protrusion29 is increased for higher speed, the requisite rigidity in theX-direction, which is the driving direction for the slider, is securedfor the protrusion 29 due to the side wall portion 24, so that it ispossible to transmit the drive force of the vibrator 20 efficiently tothe slider.

Further, the protrusion 29 exhibits resiliency at the distal endthereof, so that the resonance frequency in the vibration mode thereofis sufficiently higher than the drive frequency of the vibrator 20,making it possible to obtain a satisfactory actuator performance.Further, in the present exemplary embodiment, the protrusion 29 is of acylindrical configuration, so that it is possible to further increasethe rigidity of the side wall portion 24 as compared with the firstexemplary embodiment.

In a vibrator according to a third exemplary embodiment, the thicknessof the contact portion is equal to that of the connection portion, andthe contact portion is smaller in volume as compared with that in thesecond exemplary embodiment. FIG. 3A is a perspective view of a vibratorto which the third exemplary embodiment of the present invention isapplicable, and FIG. 3B is a perspective view, partly in section, of aprotrusion of the vibrator. The actuator of the present exemplaryembodiment is also a linear vibration type actuator, and its drivingprinciple is the same as that of the conventional linear vibration typeactuator, so that the description thereof will be omitted.

As illustrated in FIG. 3A, a vibrator 30 has a piezoelectric element 35,an elastic member 32 to which the piezoelectric element 35 is fixed, andtwo protrusions 39 protruding from one end surface of the elastic member32. As illustrated in FIG. 3B, each protrusion 39 has a cylindrical sidewall portion 34, a contact portion 36 having a contact surface 37 to bebrought into contact with a slider (not illustrated), and a connectionportion 31 connecting the side wall portion 34 and the contact portion36.

The side wall portion 34 is fixed to the elastic member 32 by laserwelding or the like via a fixation portion 33. A step is providedbetween the connection portion 31 and the contact portion 36, and theupper surface of the connection portion 31 is lower than the contactsurface 37, so that the slider does not come into contact with theconnection portion 31. The connection portion 31 is divided into four byhole portions 38 to be thereby reduced in width, whereby it is reducedin rigidity in the Z-direction and endowed with a predetermined level ofresiliency.

The step between the connection portion 31 and the contact portion 36 isformed by performing drawing on the distal end portion of the protrusion39. Thus, the contact portion 36 has a thickness equal to that of theconnection portion 31, and is reduced in volume as compared with thecontact portion 26 of the second exemplary embodiment. Thus, it ispossible to further increase the resonance frequency of the vibrationmode of the protrusion 29 as compared with that of the second exemplaryembodiment.

A vibrator according to a fourth exemplary embodiment of the presentinvention is a rotary vibration type actuator. A rotary vibration typeactuator mainly generates through excitation a progressive wave in avibrator to generate an elliptic movement in a protrusion of thevibrator. As for the construction and driving principle of the vibrator,a number of examples thereof have been discussed in Japanese PatentApplication Laid-Open No. 2006-311790, etc., so a description thereofwill be omitted.

FIG. 4 is a schematic diagram illustrating a vibrator to which thefourth exemplary embodiment of the present invention is applicable. Itis realized by applying the protrusions 29 and 39 illustrated in FIGS.2A, 2B, 3A, and 3B to the vibrator of a rotary vibration type actuator.As illustrated in FIG. 4, a vibrator 40 has a ring-shaped piezoelectricelement 45, an elastic member 42 to which the piezoelectric element 45is fixed, and a large number of protrusions 49 provided on one endsurface of the elastic member 42.

With this construction, the protrusions 49 exhibit resiliency in theZ-direction, making it possible to realize a smooth contact between thevibrator 40 and a rotor (not illustrated) constituting a driven body.Further, if the height of the protrusions 49 is increased for higherspeed, it is possible for the protrusions 49 to transmit the drive forceof the vibrator 40 efficiently to the rotor.

In a vibrator according to a fifth embodiment of the present invention,the elastic member and the protrusions are formed of the same elasticmaterial. Otherwise, the fifth exemplary embodiment is the same as thesecond exemplary embodiment, and the driving principle thereof is thesame as that of the conventional linear vibration type actuator.

FIG. 5A is a perspective view of a vibrator to which the fifth exemplaryembodiment is applicable, and FIG. 5B is a perspective view, partly insection, of a protrusion thereof. As illustrated in FIG. 5A, a vibrator50 has a piezoelectric element 55, an elastic member 52 to which thepiezoelectric element 55 is fixed, and two protrusions 59 provided onone end surface of the elastic member 52.

The elastic member 52 and the protrusions 59 are formed so as to beintegrally continuous with each other. As illustrated in FIG. 5B, eachprotrusion 59 has a cylindrical side wall portion 54, a contact portion56 having a contact surface 57 to be brought into contact with a slider(not illustrated), and a connection portion 51 connecting the side wallportion 54 and the contact portion 56, with the connection portion 51being divided into four by hole portions 58.

A step is provided so that the upper surface of the connection portion51 is lower than the contact surface 57. Thus, the slider does not comeinto contact with the connection portion 51. The connection portion(thin-walled portions 53) of the elastic member 52 with the protrusions59 is thinner in the Z-axis direction. In the case where a predeterminedlevel of resiliency can be obtained solely through a reduction in itsthickness, there is no need to divide the connection portion 51 into aplurality of parts by the hole portions 58. FIG. 12A is a perspectiveview of a vibrator illustrating a modification example of the fifthexemplary embodiment of the present invention, and FIG. 12B is aperspective view, partly in section, of a protrusion thereof. Asillustrated in FIG. 12A, a vibrator 501 has a piezoelectric element 551,an elastic member 521 to which the piezoelectric element 551 is fixed,and two protrusions 591 provided on one end surface of the elasticmember 521. As illustrated in FIG. 12B, each protrusion 591 has acylindrical side wall portion 541, a contact portion 561 having acontact surface 571 to be brought into contact with a slider (notillustrated), and a connection portion 511 connecting the side wallportion 541 and the contact portion 561. The connection portion(thin-walled portions 531) of the elastic member 521 with theprotrusions 591 is thinner in the Z-axis direction. With thisconfiguration, the protrusion 591 can have higher rigidity in-XY-planedirection, so that higher efficiency can be obtained. Further, theresonance frequency of the vibration mode, in which a connection portion511 provided at a distal end of the protrusion 591 and having resiliencyvibrates, becomes higher, thereby enabling unnecessary vibrations to berestrained.

Next, a method of manufacturing the elastic member 52 and theprotrusions 59 will be described. FIG. 6 illustrates how press moldingis performed on an elastic plate material to shape it into a finalconfiguration. In the following, the steps involved will be described.

In a first step, two hollow protrusions (which later constitute theprotrusions of a vibrator) are formed by performing drawing on a metalplate material 52 a such as a stainless steel plate illustrated in FIG.6A, which constitutes the material of the elastic member. In order thatthe plate material 52 a may not be cracked, it is advisable to performthe drawing in a plurality of steps.

FIG. 6B illustrates a midway step of the drawing operation, in whichthere are formed protrusions 59 b each composed of a continuouscylindrical side wall portion 54 b and a distal end portion (51 b, 56 b)later constituting the connection portion and the contact portion. Toprovide the protrusions 59 b through drawing, the periphery of each sidewall portion 54 b is squeezed into a thin-walled portion 53 b, with theportion of the material corresponding to this reduction in thicknessbeing caused to flow to the side wall portion 54 b. Usually, thethickness of the side wall portion 54 b is smaller than that of theplate material 52 a (52 b).

FIG. 6C illustrates the final stage of the drawing process, in whichthere are formed protrusions 59 c each composed of a continuouscylindrical side wall portion 54 c, a connection portion 51 c, and acontact portion 56 c. Along with the drawing, squeezing is performed onthe outer peripheral portion of the distal end portion 51 b illustratedin FIG. 6B in a direction opposite to the direction in which theprotrusion protrudes, whereby there is provided a thin-walled portion(connection portion 51 c), forming a step between itself and the contactportion 56 c at the center of the distal end portion.

As a result, a slider (not illustrated) to be brought into contact withthe contact surface 57 c does not come into contact with the connectionportion 51 c. Further, due to its small thickness, the connectionportion 51 c exhibits resiliency. As illustrated in FIG. 3B, the stepbetween the contact portion 56 c and the connection portion 51 c mayalso be provided by further performing drawing on the distal end portion51 b to cause the central portion of the distal end portion 51 bconstituting the contact portion to protrude farther than the outerperiphery of the distal end portion 51 b.

The second step consists of a punching process for endowing theconnection portion 51 c with a predetermined level of resiliency, andFIGS. 6D and 6E illustrate how the punching is performed. In the presentexemplary embodiment, the connection portion is divided into four toreduce the width of the connection portion, so that performing punchingat a time may involve cracking or deformation. In view of this, thepunching is performed in two stages.

As illustrated in FIG. 6D, punching is performed on two opposingportions of the four portions to forma hole portion 58 d. After this, asillustrated in FIG. 6E, punching is performed on the two remainingportions to forma plurality of connection portions 51 e having apredetermined level of resiliency due to hole portions 58 e. In the casewhere the predetermined level of resiliency can be attained withouthaving to divide the connection portion, this step is unnecessary.

The third and final step is a contour punching step for shaping theelastic member 52 e of FIG. 6E into the shape of a vibrator functioningas a vibration type actuator. FIG. 6F illustrates the ultimate shape ofthe elastic member. As illustrated in FIG. 5A, the elastic member 52 fmay be shaped into a rectangular elastic member shape in the XY-plane.As illustrated in FIG. 6F, in the case where support portions 521 forfixing the elastic member to a pedestal (not illustrated) are providedon side surfaces of the elastic member, the plate material is punchedinto a shape consisting of the elastic member and support portions.

In the present exemplary embodiment, the “shape of the vibrator” refersto the shape of the elastic member within the plane (XY-plane) in whichthe piezoelectric element is joined, or the shape consisting of theelastic member and the support portions within the plane in which thepiezoelectric element is joined. As illustrated in FIG. 6F, the supportportions 521 are provided at positions where they do not hinder thevibration of the elastic member 52 f, for example, at both longitudinalends of the elastic member, and the shape of the support portions 521may be one that does not hinder the vibration of the elastic member 52f.

As described above, by the integral presswork illustrated with regard tothe first through third steps, there is formed the elastic member 52 f,which is integrated with the protrusions 59 f. And, by joining thepiezoelectric element to the elastic member 52 f, the vibrator isformed.

In a vibrator according to a sixth exemplary embodiment, the connectionportion reaches not only the distal end of the protrusion but also tothe side surface thereof. Otherwise, it is of the same construction asthe fifth exemplary embodiment, and its driving principle is the same asthat of the conventional linear vibration actuator.

FIG. 7A is a perspective view of a vibrator according to the sixthexemplary embodiment, and FIG. 7B is a perspective view, partly insection, of a protrusion thereof. As illustrated in FIG. 7A, a vibrator60 has a piezoelectric element 65, an elastic member 62 to which thepiezoelectric member 62 is fixed, and two protrusions 69 provided on oneend surface of the elastic member 62.

The elastic member 62 and the protrusions 69 are formed integrally andcontinuously with each other. As illustrated in FIG. 7B, each protrusion69 is composed of a cylindrical side wall portion 64, a contact portion66 having a contact surface 67 to be brought into contact with a slider(not illustrated), and a connection portion 61 connecting the side wallportion 64 and the contact portion 66.

A step is provided so that the upper surface of the connection portion61 is lower than the contact surface 67, thereby preventing the sliderfrom coming into contact with the connection portion 61. The connectionportion 61 is reduced in thickness and is divided into a plurality ofportions by hole portions 68, whereby it is reduced in rigidity in theZ-direction and is endowed with a predetermined level of resiliency.

In the present exemplary embodiment, the continuous side wall portion 64is solely formed at the root of the protrusion 69, and the hole portions68 dividing the connection portion 61 reach not only the distal end ofthe protrusion but also the side surface thereof. Accordingly, theconnection portion 61 exhibits some resiliency not only in theZ-direction but also in the in-XY-plane direction. This is effective insmoothing the contact with the slider in the case where the in-XY-planecomponent of the vibration of the vibrator 60 is large. Further, at theconnection portions (thin-walled portions 63) thereof connected with theprotrusions 69, the elastic member 62 is reduced in thickness in theZ-direction.

Next, a method of manufacturing the elastic member 62 and theprotrusions 69 will be described. FIGS. 8A through 8E illustrate thesteps in which press molding is performed on the plate material of theelastic member to shape it into the ultimate shape. In the following,the steps will be described. In the first step, punching is performed ona plate material formed of a metal such as stainless steel constitutingthe elastic member 62 a illustrated in FIG. 8A, whereby there isprepared a plate material 62 b having a plurality of hole portions 68 bas illustrated in FIG. 8B.

In the second step, drawing is performed on the plate material 62 billustrated in FIG. 8B to thereby form two protrusions (which are toconstitute the protrusions of the vibrator). In order that the platematerial 62 b may not be cracked, the drawing is performed in aplurality of stages. FIG. 8C illustrates a mid stage thereof, in whichthere are formed cylindrical continuous side wall portions 64 c anddistal end portions (distal end portion centers 66 c and outerperipheral portions 61 c of the distal end portions) which laterconstitute the contact portions and the connection portions.

Each distal end portion outer peripheral portion 61 c, which laterconstitutes a connection portion, is divided into a plurality ofportions by hole portions 68 c previously formed in the first step. Inorder to provide protrusions 69 c through drawing, the periphery of eachside wall portion 64 c is squeezed into a thin-walled portion 63 c, andthe portion of the material corresponding to the reduction in thicknessthrough the squeezing is caused to flow to the side wall portion 64 c.Usually, the thickness of the side wall portion 64 c is smaller than thethickness of the plate material 62 a (62 c).

FIG. 8D illustrates the final stage of the drawing. As a result of thisdrawing, there are formed protrusions 69 d each composed of acylindrical continuous side wall portion 64 d, a connection portion 61 ddivided into a plurality of portions by hole portions 68 d, and acontact portion 66 d. Along with the drawing, squeezing is performed onthe connection portion 61 d, whereby its thickness is reduced, byforming a step between the connection portion 61 d and the contactportion 66 d.

As a result, the contact surface 67 d is higher than the upper surfaceof the connection portion 61 d, and the slider (not illustrated) doesnot come into contact with the connection portion 61 d. Further, theconnection portion 61 d has a small wall thickness and is divided into aplurality of portions, so that it exhibits a predetermined level ofresiliency in the Z-direction and, at the same time, since the sidesurface is also partly divided, it exhibits some resiliency also in theZ-direction. The step between the contact portion 66 d and theconnection portion 61 d may be provided by further performing drawing onthe distal ends of the protrusions as illustrated in FIG. 3B.

As in the fifth exemplary embodiment, in the third and final step, thereis performed contour punching to shape the elastic member 62 dillustrated in FIG. 8D into the shape of a vibrator functioning as avibration type actuator. FIG. 8E illustrates the ultimate shape of theelastic member. As illustrated in FIG. 7A, the elastic member 62 e maybe formed through punching into the shape of a rectangular elasticmember in the XY-plane, and in the case where support portions 621 areprovided as illustrated in FIG. 8F, punching is performed on thematerial into the shape of a vibrator composed of a rectangular elasticmember and support portions.

As described above, by the first through third steps of integralpresswork, there is formed an elastic member 62 e integrated with theprotrusions 69 e. And, by joining the piezoelectric element to theelastic member 62 e, the vibrator is formed.

While the present invention has been described with reference toexemplary embodiments, it is to be understood that the invention is notlimited to the disclosed exemplary embodiments. The scope of thefollowing claims is to be accorded the broadest interpretation so as toencompass all modifications, equivalent structures, and functions.

What is claimed is:
 1. A method of manufacturing a vibrator including anelastic member and a hollow protrusion having a side wall portionprotruding with respect to a surface of the elastic member, a contactportion configured to come into contact with a body, and a firstconnection portion connecting the side wall portion and the contactportion, the method comprising: forming the hollow protrusion includingthe side wall portion and a distal end portion by performing drawing onan elastic plate; and forming the contact portion and the firstconnection portion by performing drawing or squeezing on the distal endportion, wherein the contact portion is surrounded by the firstconnection portion.
 2. The method of manufacturing the vibratoraccording to claim 1, wherein the vibrator is configured to generate anelliptic movement in the hollow protrusion to thereby cause the vibratorand the body to make a relative movement.
 3. The method of manufacturingthe vibrator according to claim 1, further comprising punching theelastic plate to shape the vibrator.
 4. The method of manufacturing thevibrator according to claim 1, wherein the first connection portion hasflexibility in a direction normal to a surface of the contact portion.5. The method of manufacturing the vibrator according to claim 1,wherein, in the step of forming the hollow protrusion, the hollowprotrusion and a second connection portion connecting the hollowprotrusion and a portion of the elastic plate are formed by performingdrawing on the elastic plate.
 6. The method of manufacturing thevibrator according to claim 5, wherein a thickness of the firstconnection portion is less than a thickness of the portion of theelastic plate.
 7. The method of manufacturing the vibrator according toclaim 5, wherein a thickness of the second connection portion is lessthan a thickness of the portion of the elastic plate.
 8. The method ofmanufacturing the vibrator according to claim 5, wherein the hollowprotrusion is surrounded by the second connection portion.
 9. The methodof manufacturing the vibrator according to claim 1, wherein the vibratorcomprises a plurality of hollow protrusions, and wherein, in the step offorming the hollow protrusion, the plurality of the hollow protrusionsare formed simultaneously.
 10. The method of manufacturing the vibratoraccording to claim 1, further comprising forming a step between thecontact portion and the first connection portion by performing drawingor squeezing on the distal end portion.
 11. The method of manufacturingthe vibrator according to claim 1, further comprising forming a holeportion between the side wall portion and the contact portion.
 12. Themethod of manufacturing the vibrator according to claim 11, furthercomprising forming the hole portion by performing punching.